Light emitting diodes (LEDs) are known to provide improved optical efficiency over conventional forms of lighting, and are widely used in automotive applications. Despite their advantages, however, LEDs provide low uniformity in the output of light. In particular, individual LEDs provide a Lambertian distribution of light, such that the intensity of light is greatest immediately above the LED but diminishes when viewed from an angle.
Many automotive lighting manufacturers attempt to achieve a homogeneous lit appearance using Fresnel lenses alone or in combination with a scattering element, such as a scattering film or a textured lens. However, conventional solutions provide a segmented lit appearance due to a variety of factors. For example, a segmented lit appearance is often attributed to the difference in luminance between the bull's eye, the dioptric, and the catadioptric regions of a Fresnel lens, which drives the need of a very deep device to allow the maximum light to mix, and/or the use of expensive scattering films.
It would therefore be beneficial to provide an improved lighting device which generates a homogeneous light distribution across an illuminated area. In particular, it would be beneficial to provide improved control of light uniformity without unduly adding expense or complexity to a lighting device having one or more LED light sources.